The IODF load / resync process

In addition to the physical data which resides only in the configuration file, HCM maintains a local copy of relevant logical connectivity data from the IODF. This local copy enables HCM to display logical information without time-consuming interactions with the host. Any changes you make are written both to the local copy and to the IODF on the host. Since the local data is saved with the configuration file, HCM does not have to re-read it from the host each time the configuration file is opened. However, there are some cases where the entire contents of the local IODF database must be refreshed from the host:

  1. The first time a configuration file is created from an IODF (IODF Load). See Loading the IODF for more details.
  2. When the IODF on the host is modified outside of HCM by using, for example, the HCD ISPF interface. HCM detects that the IODF on the host is out of sync with the local copy, and re-reads the local IODF data when the configuration file is next opened (IODF Resync).
  3. Updating only one configuration file of several associated with the IODF (IODF Load and Resync).
  4. If the connection between the workstation and host is lost during an HCM session, IODF data may be more current than configuration file data, since the IODF is updated automatically but the configuration file is only updated on a Save, Close or Exit (IODF Resync).

Generally, resynchronizing the IODF logical data has the following effect on the physical configuration:

  1. New physical objects are created where appropriate.
  2. New physical connections are made as long as they do not conflict with an already existing physical connection. Existing physical connections remain.
  3. Any old physical objects and connections that are no longer mentioned in the IODF remain, except for certain physical objects that depend on the existence of corresponding logical objects. For example, a physical director is disconnected and deleted if its switch has been deleted from the IODF.

The following table gives an overview on what happens when you load an IODF or when an IODF is synchronized:

Table 1. IODF Load versus IODF Synchronize
Action Result More Information
Loading an IODF Creates a new configuration file. If you specify an already existing configuration file name, all currently stored information in the existing configuration file is completely overwritten. It is lost. See Loading the IODF
Resynchronizing IODF and configuration file The local copy of all logical configuration data in the configuration file is overwritten with the data of the IODF. The physical data is generally kept. See Resynchronizing configuration files and IODFs
Parent topic: HCM and HCD